How Wavelike Bumps Mitigate the Vortex-induced Vibration of a ‎Drilling Riser

In this paper, computational fluid dynamics is used to study how wavelike bumps influence the suppression of drilling-riser vortex-induced vibration (VIV). The numerical model involves two-dimensional unsteady incompressible turbulent flow around a cylinder, with the flow characteristics regarded as being constant. The results show that wavelike bumps are effective in mitigating the VIV, but the degree of mitigation does not increase indefinitely with the number of bumps. The mitigation is greatest with either ۵ or ۷ wavelike bumps, reducing the vibration amplitudes of the cylinder in the in-line and cross-flow directions to negligible levels. To know how equipping a circular cylinder with wavelike bumps affected its VIV response, cases with wavelike bumps of ۱, ۳, ۵, ۷, ۹, and ۱۱ are studied. 

Keywords:

Vortex-induced vibration , Wavelike bumps , Reduced velocity , Frequency spectrum , Suppression effect‎